CN100505477C

CN100505477C - Stator of rotary dynamo and its manufacture method

Info

Publication number: CN100505477C
Application number: CNB031017797A
Authority: CN
Inventors: 栅木一; 石田博士
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2003-01-22
Filing date: 2003-01-22
Publication date: 2009-06-24
Anticipated expiration: 2023-01-22
Also published as: CN1520007A

Abstract

In stator of rotary type motor, stator coil is composed of U shaped conductors sections. Each conductor section includes: U-shaped turning part as an end part of one coil setup at one end of the stator coil; inner slot part extended form the turning part and entered into slot; end part extended from slot forms a end part of another coil end part. An end part of one U-shaped conductor section is extended out along axial direction in straight, and the other end part is bent a preset angle along circumferential direction so as to form a large cooling surface.

Description

Stator of rotary motor and manufacturing method thereof

Cross reference to related applications

This application is based on and has priority over Japanese patent application 2001-379911 filed on 12/13/2001, the contents of which are incorporated herein by reference.

Technical Field

The present invention relates to a stator of a rotary electric machine and a method of manufacturing such a stator.

Background

A stator coil composed of a plurality of conductor segments that are arranged in slots of the stator and welded to each other has been proposed, and for example, japanese patent 3196738 discloses a stator coil composed of a plurality of conductor segments that are welded to each other.

In the stator coil, a pair of flat portions of a U-shaped conductor segment are placed in a pair of slots spaced apart from each other by a pole pitch, and ends of the flat portions are welded to the other pair of ends. The above-mentioned japanese patent proposes a twister for bending the end portions of a pair of to-be-welded straight portions of U-shaped conductor segments projecting in the axial direction from one end of a stator core and a lifter driver for moving the end portions in the axial direction, that is, the work for manufacturing a stator coil composed of a plurality of U-shaped conductor segments includes the step of bending the end portions of the conductor segments to weld the end portions with the other end portions. However, the above bending step is rather complicated.

Japanese patent JP- ｃA-2001-37131 discloses ｃA stator having ｃA plurality of L-shaped conductor segments which are placed in slots of the stator and whose opposite ends are welded to each other. Although this stator does not require a bending step, its welded portion and portion to be insulated are twice as many as those of a stator having U-shaped conductor segments.

Disclosure of Invention

Therefore, the present invention has been made in view of the above problems.

The main object of the present invention is to propose an improved stator for a rotary electric machine having a plurality of U-shaped conductor segments.

It is another object of the present invention to provide a simple method of manufacturing the above stator.

According to one of the main features of the present invention, a stator of a rotary electric machine has a stator core, a stator coil formed of a plurality of U-shaped conductor segments. Each conductor segment has: a U-shaped transition portion provided at one end of the stator core to form a coil end; an in-groove portion opposed to the in-groove portion; and a plurality of end portions extending from the in-slot portions to form the other coil end portion. In the above stator, each of the end portions has a straight connecting portion welded to the other end portion, the in-slot portions are aligned with each other in the radial direction, one end portion of one U-shaped conductor segment is projected straight in the axial direction, and the other end portion of the one U-shaped conductor segment is bent at a predetermined angle in the circumferential direction. The bending step is therefore very simple and, as will be described below with reference to fig. 11 and 12, each coil end has a larger cooling surface than the prior art stator.

Fig. 11 shows a pair of end portions a and b of conductor segments projecting from different slots of a stator core and bent at an angle of 45 ° in opposite circumferential directions, respectively, to form coil ends. Fig. 12 shows end portions d and c of a pair of conductor segments protruding from different slots of a stator core, the end portion c being bent at an angle of 30 ° in the circumferential direction, while the end portion d is not bent. Both coil ends have the same height 1L. However, the total length of the ends a and b is about 2.6L, and the total length of the ends c and d is 3L, which increases the cooling surface.

According to another feature of the present invention, one pair of ends of one U-shaped conductor segment is bent in the circumferential direction by 50% more than the other pair of ends, which also increases the cooling surface of the coil ends.

According to still another feature of the present invention, a method of manufacturing a stator of a rotary electric machine comprises the steps of: placing the straight portions of the plurality of U-shaped conductor segments into each slot from one end of the stator core to form radially aligned conductor layers with the ends of the straight portions extending outwardly from the other end of the stator core; bending end portions of the straight portions disposed at the predetermined conductor layer at a predetermined angle in a circumferential direction; and welding the ends of a predetermined pair of the bent end portions and the straight end portions together to form one coil end portion. This makes the stator of the above-described rotary electric machine.

According to a further feature of the present invention, a novel method comprises the steps of: bending end portions of a first group of straight portions provided on a predetermined conductor layer by a first angle in one circumferential direction; bending end portions of the second group of straight portions disposed at the remaining conductor layers in opposite circumferential directions by a second angle 50% larger than the first angle; and welding the ends of a predetermined pair of one end portion of the first group and one end portion of the second group together to form one coil end portion.

According to the present invention, there is provided a stator of a rotary electric machine, having: a stator core having a plurality of slots arranged in a circumferential direction; a stator coil having coil ends on opposite ends of said stator core, said stator coil being formed of a plurality of U-shaped conductor segments, each of said conductor segments having: a U-turn portion provided at one end of the stator core to form one of the coil ends; a pair of in-groove portions extending from said turn portions and disposed in said grooves, respectively; and end portions respectively projecting from said in-slot portions to form other coil end portions, wherein each of said end portions has a straight connecting portion directly welded to one end portion of another U-shaped conductor segment; a plurality of said in-slot portions aligned radially; one of the ends of one of the U-shaped conductor segments extends straight in the axial direction, and the other end of the U-shaped conductor segment is bent at a predetermined angle in the circumferential direction.

The invention also relates to a stator of a rotary electric machine, wherein it has: a stator core having a plurality of slots arranged in a circumferential direction thereof; a stator coil having coil ends located on opposite ends of said stator core, said stator coil being formed of a plurality of U-shaped conductor segments, each of said conductor segments having: a U-turn portion provided at one end of the stator core to form one of the coil ends; a pair of in-groove portions extending from the turning portions and being placed in the grooves, respectively; and end portions extending in the axial direction and the radial direction from the above-mentioned in-slot portions, respectively, and directly connected to end portions of the in-slot portions extending from turn portions of the other U-shaped conductor segments to form the other coil end portion, wherein one of the above-mentioned end portions of one of the above-mentioned U-shaped conductor segments is bent in the circumferential direction by an angle at least 50% larger than that of the other end portion.

The invention further relates to a method of manufacturing a stator of a rotary electric machine having a plurality of slots, the method comprising the steps of: placing straight portions of a plurality of U-shaped conductor segments into each slot from one end of said stator core to form a plurality of radially aligned conductor layers with ends of the straight portions extending outwardly from the other end of said stator core; bending the end portions of the straight portions disposed in the predetermined conductor layer by a predetermined angle in the circumferential direction; and welding the bent end portion of one of the U-shaped conductor segments and the distal end of one of the straight end portions of the other U-shaped conductor segment to constitute one coil end portion.

The present invention still further relates to a method of manufacturing a stator having a plurality of slots of a rotary electric machine, the method comprising the steps of: placing a plurality of straight portions of U-shaped conductor segments into each slot from one end of said stator core to form a plurality of radially aligned conductor layers with the ends of said straight portions extending outwardly from the other end of said stator core; bending the ends of a first group of said straight portions disposed in a predetermined conductor layer by a first angle in the circumferential direction; bending the ends of a second set of said straight portions disposed in the remaining of said conductor layers in another circumferential direction by a second angle that is 50% greater than said first angle; and welding one end portion of one of the U-shaped conductor segments of the first group to a distal end of one end portion of another one of the U-shaped conductor segments of the second group to form one coil end portion.

Drawings

Other objects, features and characteristics of the present invention, as well as the functions of the related elements of the present invention, will become apparent upon review of the following detailed description, the appended claims, and the accompanying drawings, in which:

fig. 1 is a sectional view of a vehicle alternator having a stator of a first embodiment of the present invention;

FIG. 2 is a perspective view of a pair of U-shaped conductor segments of the stator shown in FIG. 1;

fig. 3 is a partial sectional view of the stator;

FIG. 4 is a perspective view of a pair of U-shaped conductor segments inserted into a pair of slots of a stator;

FIG. 5 is a side sectional view of the winding former;

fig. 6 is a plan view of the twister;

FIG. 7 is a partial side view of the stator;

fig. 8 is a partial plan view of a pair of U-shaped conductor segments mounted in a pair of slots of a stator core and bent in a predetermined manner;

FIG. 9 is a partial side view of a stator manufactured in another bending process;

fig. 10 is a partial plan view of a pair of U-shaped conductor segments mounted in a pair of slots of a stator core and bent in a predetermined manner;

FIG. 11 is a schematic illustration of the relationship between the bend angle of a prior art U-shaped conductor segment and its coil end length; and

fig. 12 is a schematic view of the relationship between the bending angle of the U-shaped conductor segments of the stator of the present invention and the coil end lengths thereof.

Detailed Description

As shown in fig. 1, a vehicle alternator 1 has a rotor 2, a stator 3, a casing 4, a rectifier 5, an output terminal 6, a rotating shaft 7, a pair of brushes 8, and a pair of slip rings 9. The stator 3 has a stator coil 31 and a stator core 32 fixed to the inner circumference of the housing 4. The stator coil 31 is mounted in a plurality of slots formed in the stator core 32. The rotor 2 has a rotor core 71 and a field coil 72 wound around a central projection of the rotor core 71 and is radially disposed inside the stator 3. The stator coil 31 is a 3-phase armature winding having 3 ac output terminals for supplying a 3-phase ac voltage, which is converted by the rectifier 5 and outputs a dc voltage at the output terminal 6. The field coil 72 is excited by a field current supplied through the brush pair 8 and the slip ring pair 9 to generate a magnetic field. The field current is controlled by a regulator (not shown) to regulate the output voltage.

The stator coil 31 is constructed as follows. As shown in fig. 2, a pair of

U-shaped conductor segments

331 and 332 are placed into a pair of slots from one end of the stator core 32. Both ends of the conductor segments are protruded from the other end of the stator core 32 by a desired height. Then, the ends of the plurality of conductor segments are bent in the circumferential direction by a predetermined angle so that the connecting portions thereof can be welded to the connecting portions of another group of conductor segments. The stator core 32 has 36 slots disposed at equal angular distances along its inner surface. The two

U-shaped conductor sections

331, 332 have U-shaped strip portions covered with an insulating material film (except for connecting portions on opposite ends thereof).

The stator coil 31 has an annular first coil end portion 311 provided at one end of the stator core 32, an annular second coil end portion 312 provided at the other end of the stator core 32, and a plurality of in-slot portions located in the slots.

As shown in fig. 2, there are two kinds of U-shaped conductor segments, i.e., a large conductor segment 331 and a small conductor segment 332, the large conductor segment 331 has a pair of in-

slot portions

331a and 331b, a turn portion 331c, and a pair of

end portions

331f and 331g, the

end portions

331f and 331g having connecting

portions

331d and 331e, respectively. In the above, the in-slot portion 331a is referred to as an inner-slot portion, and the in-slot portion 331b is referred to as an outer-slot portion. The small conductor segment 332 has a pair of in-

slot portions

332a and 332b, a turn portion 332c, and a pair of

end portions

332f and 332g, the

end portions

331f and 331g having connecting

portions

332d and 332e, respectively. The above-described in-slot portion 332a is referred to as an inner-slot portion, and the in-slot portion 332b is referred to as an outer-slot portion. Reference numerals with "'" in fig. 2 denote parts corresponding to parts denoted by the same reference numerals. That is, the connecting portion 332d and the connecting portion 331d ' arranged side by side in the radial direction are welded together, the connecting portion 332e and the connecting portion 331e ' are welded together, and the connecting portion 332e and the connecting portion 331e ' are welded together. Thus, the first coil end 311 is constituted by the

ends

331f and 331g, 332f and 332g of the

U-shaped conductor segments

331, 332, and the second coil end 312 is constituted by the

turn portions

331c and 332c of the

U-shaped conductor segments

331, 332.

The above-mentioned inner-

slot portions

331a, 332a are placed in one of a pair of slots 35 which is separated from the other slot placed in the above-mentioned outer-

slot portions

331b, 332b by one pole pitch of the rotor core 71, and therefore, the turn portions 332c of the small conductor segments 332 are closed by the turn portions 331c of the large conductor segments 331.

As shown in fig. 3, inner slot inner portion 331a is disposed at a radially innermost position of slot 35, inner slot portion 332a is disposed at an inner intermediate position, inner slot portion 322b 'is disposed at an outer intermediate position, and inner slot portion 331 b' is disposed at an outermost position. Thus, within each slot 35 there are disposed 4 radially aligned in-slot portions. The inner groove inner portions 331a 'and 332 a' corresponding to the above-described groove inner portions 331b 'and 332 b' are arranged in another groove separated by one pole pitch. Incidentally, reference numeral 34 denotes an insulator.

The end 331g extending from the outer in-slot portion 331b of the large conductor segment 331 is bent in one circumferential direction by a first angle, and the end 331f extending from the outer in-slot portion 331a of the large conductor segment 331 is bent in the other circumferential direction by a second angle, the total of the first angle and the second angle being bent by a polar distance.

Then, the radially innermost connecting portion 331d and the radially innermost connecting portion 332d 'of the inner intermediate layer are welded together, and the radially outermost connecting portion 332e and the radially innermost connecting portion 331 e' of the outer intermediate layer are welded together by a welding machine such as a Tungsten Inert Gas (TIG) welding machine, an electric resistance welding machine, an electron beam welding machine, or a laser welding machine, see fig. 2.

As shown in fig. 5 and 6, the winding former 500 has: a working bracket 51 supporting the stator core 32; a jig 52 for holding the stator core 32; a working press 53 pressing the stator core against the working holder 51; a twister 54 for bending the straight portions of the U-shaped conductor segments; a lifting rod 54a for moving the twister 54 up and down; 4 rotation mechanisms 541a to 544a for rotating the twister 54; a lift lever driver 54b for driving the lift lever 54 a; and a controller 55 for controlling the rotating mechanisms 541a to 544a and the lifter driver 54 b.

The twister 54 is composed of 4 axial rotation members 541-544. Each of the rotating members 541 to 544 has a cylindrical portion and a flange portion which are independently rotatable. The upper ends of the 4 cylindrical portions are flush with each other. As shown in fig. 6, a plurality of clamping

grooves

541b, 542b, 543b, and 544b distributed in the circumferential direction are respectively formed at the upper end of each of the 4 cylindrical portions so as to clamp the

ends

331f, 331g, 332f, and 332g of the conductor segment. The number of the holding grooves of each of the rotating members 541 to 544 is the same as the number of the grooves 35 of the stator core 32. The holding grooves 541b to 544b of the radially adjacent rotor are separated by the isolation regions 541c to 544c and 542d to 543d, that is, the holding groove 541b of the rotor 541 and the holding groove 542b of the rotor 542 are separated by the isolation region 541c of the rotor 541 and the isolation region 542c of the rotor 542 by a distance d1, the holding groove 542b of the rotor 542 and the holding groove 543b of the rotor 543 are separated by the isolation region 542d of the rotor 542 and the isolation region 543d of the rotor 543 by a distance d2, and the holding groove 543b of the rotor 543 and the holding groove 544b of the rotor 544 are separated by the isolation region 543c of the rotor 543 and the isolation region 544c of the rotor 544 by a distance d 3. The distance d2 formed by the

distance zones

542d and 543d between the second rotary member 542 and the third rotary member 543 is longer than both the distances d1 and d 3. Therefore, the distance between the ends of the

conductor segments

331 and 332 protruding from the first and second layers is short enough to connect their connecting portions to each other, and the distance between the ends protruding from the third and fourth layers is short enough to connect their connecting portions to each other. On the other hand, the distance between the end portion extending from the third layer and the end portion extending from the third layer is long enough to insulate them from each other.

First, the stator core 32 with the

conductor segments

331, 332 inserted into the slots 35 is placed on the working bracket 51. The stator core 32 is then clamped from the outside by the clamp 52. The upper end of the stator core 32 and the top of the turn portion of the large conductor segment 331 are then pressed by the working press 53, thereby restricting the vertical movement of the stator core 32 and the

conductor segments

331, 332. Then, the twister 54 is raised by the lifter 54a, and the

end portions

331f, 331g, 332f, and 332g of the conductor segments, which are the connection portions, are inserted into the holding grooves 541b to 544b by an appropriate length. The end portions are preferably tapered so as to be smoothly inserted into the holding grooves 541b to 544 b. The rotating members 541 to 544 of the twister 54 are rotated and vertically moved simultaneously by the rotating mechanisms 541a to 544a, the lift lever 54a, and the lift lever driver 54 b. That is, the first and third

rotating members

541 and 543 are rotated clockwise by a first angle, and the second and fourth

rotating members

542 and 544 are rotated counterclockwise by a second angle.

Importantly, the first angle is at least 50% greater than the second angle. Therefore, the

end portions

331f, 331g, 332f, and 332g that project outward from the groove 35 are bent (except for the portions that are placed in the holding grooves 541b to 544 b). Then, the lifter driver 54b and the rotating mechanisms 541a to 544a are controlled to rotate and raise the twister so that the lengths of the

end portions

331f, 331g, 332f and 332g are kept constant, and the

end portions

331f, 331g, 332f and 332g are raised and rotated to draw a circle, which movement is continued until the above-mentioned angle is larger than a predetermined angle by a half pole pitch, to prevent the conductor segment from being deformed by the elastic return. Since the

end portions

331f, 331g, 332f and 332g have been bent at their portions adjacent to the slots 35, the conductor segments do not fall off away from the stator core 32.

Then, the lifter driver 54b is moved downward and the rotating mechanisms 541a to 544a are rotated in reverse, so that the

end portions

331f, 331g, 332f and 332g are separated from the holding grooves 541b to 544b, and the rotating mechanisms 541a to 544a are returned to the original positions. Finally, the clamp 52 and the press 53 are released and the stator with the

U-shaped conductor sections

331, 332 is removed.

Those

end portions

331f, 331g, 332f and 332g which are adjacent to each other are welded together at connecting

portions

331d, 331e, 332d and 332e to constitute a 3-phase stator coil having a desired number of turns, see fig. 7 and 8 (only one pair of

conductor segments

331, 332 is shown).

As shown in fig. 9 and 10, the

conductor segments

331, 332 may be bent differently. In this embodiment, the end 331g extending from the outermost in-slot portion 331b is bent by one pole pitch in the circumferential direction, while the end 331f extending from the innermost in-slot portion 331a is not bent but remains straight. Likewise, the end 332g extending from the outer intermediate in-slot portion 332b is curved in the circumferential direction by a polar distance, while the end 332f extending from the inner intermediate in-slot portion 332a is not curved and remains straight. That is, the ends disposed at the second and fourth layers are bent in the circumferential direction by 6 pitches, while the ends disposed at the first and third layers are protruded straight. Therefore, in this case, the rotating

members

542 and 544 and the rotating mechanism thereof shown in fig. 5 can be omitted.

The above-described winding die 500 can be applied to other various types of stators only by changing the

rotation members

541, 542, 543 and 544 of the twister 54 thereof. For example, winding formers for rotating members having 48, 84, and 96 clamping slots can be applied to stators having a corresponding number of slots.

In the foregoing specification of the invention, the invention has been disclosed with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader scope of the invention as set forth in the appended claims. The foregoing description of the invention is, therefore, to be regarded as illustrative rather than restrictive.

Claims

1. A stator for a rotary electric machine, comprising:

a stator core (32) having a plurality of slots (35) arranged in a circumferential direction;

a stator coil having coil ends (311, 312) located at opposite ends of said stator core (32), said stator coil being formed of a plurality of U-shaped conductor segments (331, 332), each of said conductor segments having: a U-turn portion (331c, 332c) provided at one end of the stator core (32) to form one (312) of the coil ends (311, 312); a pair of in-groove portions (331a, 331b, 332a, 332b) extending from the turn portions (331c, 332c) and disposed in the groove (35); and end portions (331f, 331g, 332f, 332g) respectively projecting from the above-mentioned in-slot portions (331a, 331b, 332a, 332b) to form the other coil end portion (311),

wherein,

each of said ends (331f, 331g, 332f, 332g) having a straight connecting portion (331d, 331e, 332d, 332e) welded directly to one end of another U-shaped conductor segment;

a plurality of the above-mentioned in-slot portions (331a, 331b, 332a, 332b) are arranged in radial alignment;

one of the end portions (331f, 331g, 332f, 332g) of one of the U-shaped conductor segments (331, 332) is extended straight in the axial direction, and the other end portion of one of the U-shaped conductor segments (331, 332) is bent at a predetermined angle in the circumferential direction.

2. A stator for a rotary electric machine, comprising:

a stator core (32) having a plurality of slots (35) arranged in a circumferential direction thereof;

a stator coil having coil ends (311, 312) located at opposite ends of said stator core (32), said stator coil being formed of a plurality of U-shaped conductor segments (331, 332), each of said conductor segments having: a U-turn portion (331c, 332c) provided at one end of the stator core to form one of the coil ends (311, 312); a pair of in-groove portions (331a, 331b, 332a, 332b) extending from the turn portions (331c, 332c) and inserted into the groove (35); and end portions extending axially and radially from the above-mentioned in-slot portions (331a, 331b, 332a, 332b), respectively, which are directly connected to end portions of in-slot portions extending from turn portions of another U-shaped conductor segment to form another coil end portion,

wherein one of said end portions (331f, 331g, 332f, 332g) of one of said U-shaped conductor segments (331, 332) is bent in a circumferential direction by an angle at least 50% greater than an angle at which the other end portion of one of said U-shaped conductor segments (331, 332) is bent in the circumferential direction.

3. A method of manufacturing a stator of a rotary electric machine having a plurality of slots (35), the method comprising the steps of:

placing straight portions of a plurality of U-shaped conductor segments (331, 332) into each slot (35) from one end of said stator core to form a plurality of radially aligned conductor layers with end portions (331f, 331g, 332f, 332g) of the straight portions extending outwardly from the other end of said stator core;

bending end portions (331f, 331g, 332f, 332g) of the straight portions disposed in the predetermined conductor layer by a predetermined angle in a circumferential direction; and

the bent end of one U-shaped conductor segment and the distal end (331d, 331e, 332d, 332e) of a straight end of another U-shaped conductor segment are welded together to constitute a coil end (311).

4. A method of manufacturing a stator of a rotary electric machine having a plurality of slots (35), the method comprising the steps of:

placing straight portions of a plurality of U-shaped conductor segments (331, 332) into each slot (35) from one end of said stator core to form a plurality of radially aligned conductor layers, with the ends (331f, 331g, 332f, 332g) of said straight portions extending outwardly from the other end of said stator core;

bending end portions (332g, 331f) of a first group of the above-mentioned straight portions disposed in a predetermined conductor layer by a first angle in a circumferential direction;

bending the ends (331g, 332f) of a second set of said straight portions disposed in the remaining of said conductor layers in another circumferential direction by a second angle which is 50% greater than said first angle; and

welding together one end of one of the U-shaped conductor segments of the first group and a tip (331d, 331e, 332d, 332e) of one end of another U-shaped conductor segment of the second group to form one coil end (311).